1. Field of the Invention
The present invention relates to a position detecting apparatus for detecting a position of a driving member that linearly moves or rotates, and more particularly to a magnetic position detecting apparatus using magnetism.
2. Description of the Related Art
As a position detecting apparatus of this type, Examined Japanese Patent Publication Sho. No.54-41335 (prior art 1) discloses a structure in which one and the other magnetic resistance circuits, each having multiple magnetic resistance elements connected in series, are formed in a comb shape and one and the other magnetic resistance circuits are horizontally arranged along a magnetic pole array direction.
Unexamined Japanese Patent Publication Hei. No. 7-4987 (prior art 2) discloses a technique in which a groove is formed on a magnetized surface to shape an output waveform from a magnetic resistance circuit at a reference position.
However, in the technique of prior art 1, since the multiple magnetic resistance circuits in the magnetic position detecting apparatus are arranged along the magnetic pole array direction, when one magnetic resistance circuit has numerous magnetic resistance elements or numerous magnetic resistance circuits are provided, there is a problem in which the length in the circuit in the magnetic pole array direction is increased to cause enlargement in size of the position detecting apparatus and a decrease in resolution of the output waveform.
Moreover, in prior art 2, when the multiple magnetic resistance circuits are provided, there occurs a problem of enlargement in size of the position detecting apparatus, similar to prior art 1. Furthermore, in the position detecting apparatus for the driving member that rotates, there is a problem in which when a length of a position detecting apparatus in a width direction (magnetic pole array direction) is increased, electric field strength, which is received at both ends of the position detecting apparatus in the width direction, is reduced by its positional shift, so that resolution of the output waveform is decreased.